Piston seal



Feb.10, 1942. c. SAUZEDDE 2,272,327

PISTON SEAL Original Filed Oct. 50, 1936 2 Sheets-Sheet 2 INVENTOR. C/(&((0 8 5cm cdoe,

ATTORNEY.

Patented Feb. 10, 1942 PISTON SEAL Claude Sauzedde, Detroit, Mich,assignor to Detroit Hydrostatic Brake Corporation, Detroit,

Mich., a corporation of Michigan Original application October 30, 1936,Serial No. 108,351, now Patent No. 2,200,305, dated May 1940, Serial No.334,834

4 Claims.

This invention relates to means for sealing chambers in whichreciprocating elements are mounted for movement in response to fluidpressure in the chambers, or wherein the elements are to be moved bypressure means arranged externally of the chambers for exerting pressureon fluid in the chambers in which they are mounted, and is a division ofmy co-pending application, Ser. No. 108,351, filed October 30, 1936, andentitled Piston seals (now Patent No. 2,200,- 305). It refers moreparticularly to hydrostatic braking systems wherein pistons movablyreceived in chambers and connected to brake shoes are moved with respectto their chambers by fluid under pressure.

One of the objects of the present invention is to provide a sealingmeans between the wall of a piston and the wall of a cylindrical chamberin which it operates in response to fluid pressure which is positivelynon-leakable and which is designed to embody high wear-resistingproperties. The sealing means is in the form of an open-ended cylinderand is comprised of elastic material, such as rubber, and this means hasan annular, metallic reinforcement surface bonded or vulcanized to eachend thereof. In assembling the seal in a brake of the hydrostatic type,one of the metallic reinforcing members is clamped to the wall of thecylinder and the other metallic reinforcing member is clamped-to thewall of the piston which operates in the cylinder. This manner ofclamping the annular reinforcements to the walls of the cylinder andpiston provides for a pair of metal-to-metal contacts and permits theclamping parts to be tightened into such firm engagement that leakage offluid past the piston is positively prevented. These metal-to-metalcontacts are also advantageous in that they permit sealing elements ofthe deformable, soft metal type to be positioned between the clampedparts to enhance the sealing action and render it absolutely positive.

Another object is to provide a new and improved seal at the wheel brakeof a hydrostatic braking system which is more easily assembled and lessneedful of adjustments and repairs than heretofore.

With the above and other ends in view the invention consists in mattershereinafter more particularly set forth with reference to theaccompanying drawings, in which Figure 1 is a vertical section of thestructure at the wheel brake;

Fig. 2 is a vertical section taken on a plane transverse to Fig. 1;

Divided and this application May 13,

Fig. 3 is a vertical section of a modified brake construction;

Fig. 4 is a view taken on the line 4-4 of Fig. 3; and

Fig. 5 is a section of another form of seal.

Like characters of reference are employed throughout to designatecorresponding parts.

The numeral I designates a fragment of a spider such as ordinarilyprovides the support for brakes within a vehicle wheel. Such spiders andbrake assemblies with respect to vehicle wheels are already well knownin the art and, therefore, are not shown in detail here. Integral withthe spider are two guide arms 2 between which a bridge member 3,supporting brake shoes 4, is slidable radially. Between the arms 2 thespider is formed with a cylindrical projection 5 with its axis extendingradially. At its outer end the cylindrical projection 5 has a co-axial,internally threaded, annular formation 6 the outer diameter of which isless than the diameter of the projection 5 so as to form a shoulder l.The face of the shoulder l is formed in a plane normal to the axis ofthe annular formation 6 and is smoothly machined.

A cylindrical body or sleeve 8, formed of rubber, has an annular,metallic reinforcement 9 surface bonded to its lower end, thereinforcement being internally disposed with respect to the end of thesleeve and having serrations on its external surface for increasing thetenacity of the surfacebonding. The end of the sleeve 8 may bevulcanized to the reinforcement 9, for example, or it may be securedthereto by suitable adhesives. At its other end the sleeve 8 has anotherannular, metallic reinforcement 10 surface bonded thereto, externallythereof, the inner surface of said reinforcement also being providedwith serrations for reasons similarly as above.

Received in the annular formation 6 is a screwthreaded clamping elementH having a shoulder l2 which bears against the annular reinforcement 9to press the latter into firm engagement with the shoulder l. Adeformable sealing element 12a, that is, a sealing element of softmetal, such as aluminum, is placed between the shoulder l2 and thereinforcement 9 and extends along and between said shoulder and the endsurface of the annular formation 6. By tightening the clamping elementII, the contacting surfaces of the shoulder l, annular reinforcement 9and shoulder I2 may be brought into such firm engagement that passage offluid therebetween is impossible.

Loosely received between the arms 2 is an element l3 having acylindrical formation l4 disposed within the upper end of the sleeve 8.The upper end of the element l3 supports the bridge member 3 and thisend is provided with an externally threaded portion l5 and a shoulderIt. A hollow cylindrical body formed with an internal shoulder i8, isscrewthreaded onto the screwthreaded portion i5 and the annularreinforcement I0 is clamped between the shoulders I6 and I8 thereby. Adeformable seal i9, similar to the seal |2a and formed of aluminum, forexample, is positioned between the annular reinforcement l9 and theshoulder It. The hollow cylindrical body I! encloses the elastic sleeve8 and its lower end finds bearing on the cylindrical projection 5.

The spider is provided with passages which communicate with a port 2|extending through the clamping element I and serve to convey fluid underpressure to the space between the elements II and I3. When fluid underpressure is introduced to this space, the element I 3 moves radiallyoutwardly with respect to the spider I and engages the bridge member 3to force the brake shoes 4 outwardly. During such movement of theelement I3, the elastic sleeve 8 is stretched but is prevented fromexpanding radially of itself by the confining surfaces of thecylindrical body H. The two elements H and i3 are maintained in co-axialalignment during such movement by engagement of the lower end of thehollow cylindrical body I? with the cylindrical projection 5.

Referring to Figs. 3 and 4, there is illustrated a stationary spider 38having a radially projecting shank 3| with guide portions 32. Slidablyreceived upon the guide surfaces 32 is a cross member 33 which supportsa pair of brake shoes 34, one of said shoes being shown in Fig. 3. Atthe base of the shank 3| is provided a shoulder 35, and a cylindricalretainer 36, which is secured upon a screwthreaded portion 31 of saidshank, clamps an annular metallic reinforcement 38 against the shoulder35. An elastic seal 33 has on end thereof surface bonded to thereinforcement 38 and its other end is surface bonded to an annularprojection 40 on a movable element 4!. Surrounding the base of the shank3| is an annular formation 42 screwthreadedly receiving a retainer 43which clamps an annular metallic reinforcement 44 against the shoulder35. One end of an elastic sleeve 45 is surface bonded to the innersurface of the annular reinforcement 44 and its other end is surfacebonded to the annular projection M] on the movable element 4|.

The two sleeves 39 and 45 are thus concentrically disposed and the spacetherebetween constitutes a fluid pressure chamber. The spider 30 isprovided with passages 46 for conveying fluid under pressure to thespace between the two concentric, elastic sleeves. An annular filler 41is mounted between the two sleeves 39 and 45 to oc cupy a major portionof the space therebetween so as to reduce the amount of fluid necessaryto fill such space.

When fluid under pressure is supplied through the passages 46 to thepressure chamber formed as above described, it acts upon the filler 4'1and the annular projection 40 to move the movable element 4| outwardlywith respect to the shank 3|. During such movement, the movable element4| engages the cross member 33 and forces the shoes 34 outwardly forcontact with a brake drum. The usual springs, not shown, are' used toretract the shoes and to move the cross member 33 and movable element 4|back to the position shown in Fig. 3.

In Fig. 5, there is shown a modified seal adapted for assembly in abrake construction, such as shown in Fig. 3. In this form the sealcomprises inner and outer annular walls 50 and 5|, respectively, the twowalls being of different diameters whereby a space 52 is providedtherebetween. The space between the two walls 50 and 5| is closed at oneend by an integral annular wall 53 preferably having a comparativelyhard surface portion, as indicated at 54. Surface bonded internally tothe open end of the wall 58 is an annular metallic reinforcement 55 andsurface bonded externally to the outer wall 5| is an annular metallicreinforcement 56.

In assembling the seal shown in Fig, 5, in a brake such as shown in Fig.3, the two reinforcements 55 and 55 are clamped against the shoulder 35by retainers, such as shown at 35 and #3, respectively.

Although a specific embodiment of the invention has been illustrated anddescribed, it will be understood that various changes may be made withinthe scope of the appended claims without departing from the spirit ofthe invention, and such changes are contemplated.

What I claim is:

1. In a hydrostatic brake, a movable brake actuator, a stationarysupport for said actuator, a fluid chamber formed between said actuatorand said support, means for conveying fluid under pressure to saidchamber for actuating said actuator, an open-ended, cylindrical,flexible sealing member arranged between said actuator and said supportfor sealing said fluid within said chamber, an annular metallic memberconnected in sealed relationship to each end of said sealing member andanchored one to said actuator and one to said support for reinforcingsaid ends and providing a unitary structure comprising said actuator,said support, said sealing member and said metallic members, and anotherpair of annular metallic members one arranged between said actuator andone of said first annular members and the other arranged between saidsupport and the other of said first annular members.

2. In a hydrostatic brake, a movable brake actuator, a stationarysupport for said actuator, a fluid chamber formed between said actuatorand said support, means for conveying fluid under pressure to saidchamber for actuating said actuator, an open-ended, cylindrical,flexible sealing member arranged between said actuator and said supportfor sealing said fluid within said chamber, a pair of annular metallicmembers connected in sealed relationship one to one end of said sealingmember exteriorly of the latter and the other to the other 'end of saidsealing member interiorly of the latter and anchored one to saidactuator and one to said support for reinforcing said ends and providinga unitary structure comprising said actuator, said support, said sealingmember and said metallic members, and another pair of annular metallicmembers one arranged between said actuator and one of said first annularmembers and the other arranged between said support and the other ofsaid first annular members.

3. In a hydrostatic brake, a movable brake actuator formed with a pairof concentrically arranged, annular surfaces, a stationary support forsaid actuator and formed with an annular surface substantially equal indiameter to the inner surface of said pair, a fluid ch'amber formedbetween said actuator and said support within the confines of said innersurface, means for conveying fluid under pressure to said chamber foractuating said actuator, an open-ended, cylindrical, flexible sealingmember arranged between said surfaces of said pair and about said thirdsurface for sealing said fluid within said chamber, an annular metallicmember connected in sealed relationship to each end of said sealingmember and anchored one to said actuator and one to said support forreinforcing said ends and providing a unitary structure comprising saidactuator, said support, said sealing member and said metallic members,and another pair of annular metallic members one arranged between saidactuator and one of said first annular members and the other arrangedbetween said support and the other of said first annular members.

4. In a hydrostatic brake, a movable brake actuator formed with a pairof concentrically arranged, annular surfaces, a stationary support forsaid actuator and formed with an annular surface substantially equal indiameter to the inner sur face of said pair, a fluid chamber formedbetween said actuator and said support within the confines of said innersurface, means for conveying fluid under pressure to said chamber foractuating said actuator, an open-ended, cylindrical, flexible sealingmember arranged between said surfaces of said pair and about said thirdsurface for sealing said fluid within said chamber, a pair of annularmetallic members connected in sealed relationship one to one end of saidsealing member exteriorly of the latter and the other to the other endof said sealing member interiorly of the latter and anchored one to saidactuator and one to said support for reinforcing said ends and providinga unitary structure comprising said actuator, said support, said sealingmember and said metallic members, and another pair of annular metallicmembers one arranged between said actuator and one of said first annularmembers and the other arranged between said support and the other ofsaid first annular members.

CLAUDE S-AUZEDDE.

